From a makeshift pulpit inside an Indiana Quality Inn, a baby-faced priest angrily denounces the Jews, saying they mean to "destroy all Christian nations." In offices in State Line, Pa., an intense, bespectacled man tirelessly recounts how the 1911 Catholic Encyclopedia "predicts the anti-Christ will come from Jewry" and warns of the Jews' role in the coming "New World Order." At a gathering near the Philadelphia airport, men in priests' collars and brown monk's robes rage against the "Judeo-Masonic" conspiracy to destroy the Catholic Church, the "Marxist-Jewish" scheme to wreck American schools, and even an elaborate 9/11 plot, "predicted by...